GO2-89-214, Application for Amend to License NPF-21,amending Tech Spec 4.3.6-1, Source Range Monitor/Intermediate Range Monitor (Srm/Irm) Detector Not-Full-In Functional Test Such That Required Weekly Channel Test Surveillance Met as Stated
| ML17285A872 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 11/29/1989 |
| From: | Sorensen G WASHINGTON PUBLIC POWER SUPPLY SYSTEM |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML17285A873 | List: |
| References | |
| GO2-89-214, NUDOCS 8912110139 | |
| Download: ML17285A872 (16) | |
Text
REGULATORY eEORMATION DISTRIBUTION BY@M (RIDE)
ACCESSION NBR:.8912110139 DOC.DATE: 89/11/29 NOTARIZED: YES DOCKET FACIL:50".397 WPPSS Nuclear Project, Unit 2, Washington Public Powe 05000397 AUTH.NAME AUTHOR AFFILIATION SORENSEN,G.C.
Washington Public Power Supply System RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)
SUBJECT:
Application for amend to License NPF-2l,amending Tech Spec 4.3.6-1, "Source Range Monitor/Intermediate Range Monitor (SRM/IRM) Detector Not-Full-In Functional Test" such that required weekly channel test surveillance met as stated.
DISTRIBUTION CODE: A001D COPIES RECEIVED:LTR I
ENCL
/
SIZE:
1 TITLE: OR Submittal: General Distribution NOTES:
RECIPIENT ID CODE/NAME PD5 LA SAMWORTHiR COPIES LTTR ENCL 1
1 5
5 RECIPIENT ID CODE/NAME PD5 PD COPIES LTTR ENCL 1
1 INTERNAL: ACRS NRR/DOEA/OTSB11 NRR/DST/SELB 8D NRR/DST/SRXB 8E REG FILE 01 EXTERNAL: LPDR NSIC 6
6 1
1 1
1 1
1 1
0 1
1 1
1 1
1 NRR/DET/ECMB 9H NRR/DST 8E2 NRR/DST/SICB 7E NUDOCS-ABSTRACT OGC/HDS2 RES/DSIR/EIB NRC PDR 1
1 1
1 1
1 1
1 1
0 1
1 1
1 TOTAL NUMBER OF COPIES REQUIRED:
LTTR 27 ENCL 25
WASHINGTON PUBLIC POWER SUPPLY SYSTEM P.o. Box 968
~ 3000 George Washington Way
~ Richland, Washington 99352 November 29, 1989 G02-89-214 Docket No. 50-397 U.
S. Nuclear Regulatory Commission Attn:
Document Control Desk Washington, D.C.
20555 Gentlemen:
Subject:
Reference:
NUCLEAR PLANT NO. 2, OPERATING LICENSE NPF-21 REQUEST FOR AMENDMENT TO TECHNICAL SPECIFICATION TABLE 4.3.6-1, SRH/IRH DETECTOR NOT-FULL-IN FUNCTIONAL TEST 1)
WNP-2 FSAR Section 15.4 2)
NEDC-30851P, Supplement 1 "Technical Specification Improvement Analysis for BWR Control Rod Block Instrumentation",
dated October 1988 In accordance with the Code of Federal Regulations, Title 10, Parts 50.90 and
- 2. 101, the Supply System hereby submits a
request for amendment to the WNP-2 Technical Specifications.
Specifically, the Supply System is requesting that weekly channel functional test surveillance required for the SRHs and IRHs be met for MODE 5 if the detectors are verified to remain full-in at least once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and the SRM/IRM drive control system administratively controlled in the fully inserted position to preclude withdrawal by inadvertent operator action.
This will preclude the need to withdraw the detectors to verify the rod block function, provided this verification is performed within the past 92 days.
There are 4
SRM and 8 IRH channels.
Each includes a fission chamber detector and associated cable which can be positioned in the reactor vessel from above the fuel centerline to 30 inches below the fuel region.
The detector is designed and installed to be inserted from under the vessel into a dry tube sealed against reactor vessel pressure.
Each detector has a
drive system which positions the detector within the dry tube.
8912110139 891129 PDR ADOCK 05000397 P
PNU o>
P I
~ "8 1
'lf
Page Two RE(VEST FOR AMENDMENT TO TS TABLE 4.3.6-1 SRH/IRH DETECTOR NOT-FULL-IN FUNCTIONAL TEST In Mode 5 the SRH/IRM detectors can provide two signals to prohibit rod movement:
a detector not-full-in signal or an upscale scram/rod block signal.
These provide backup to the non-safety related refueling interlocks described in Section 7.7. 1. 13 of the WNP-2 FSAR.
As discussed in that section refueling interlocks are provided from logic combinations of all-,rods-in signals, refueling platform position signals, rod selection signals, mode switch in "refuel" signal, and fuel-loaded signals from either the refueling or service platform hoists.
These refueling interlocks are surveyed weekly during refueling to confirm operability.
The SRM/IRH signals are provided so that in the event of an initial equipment failure followed by any other single equipment failure or operator
- error, one or both of the SRH/IRM Rod Block functions actuate to provide a rod movement block signal (WNP-2 FSAR 15.4. 1. 1.2.6).
Removing the requirement to perform the weekly channel functional test of the detector not-full-in signal
'reates a potential for this backup function to fail and not be detected and also allow the detector to be moved out of position so that it would not provide a
scram/rod block signal in the event of the above equipment failures and/or operator errors.
The Supply System recognizes this potential loss of reliability when viewed by itself but considers it to be more than offset by the compensatory measures that will be implemented with the proposed change.
Further with respect to the hardships and challenges to system reliability described below the proposed change is an improvement to overall plant safety and reliability.
The weekly surveillance test in MODE 5 creates an undue hardship for the plant staff and impacts the operability and reliability of the SRH/IRH equipment for no appreciable assurance of safety over that of the proposed change.
During each refueling outage Control Rod Drive maintenance and other work in the under core region requires that the SRH/IRH cables be rolled up and tied out of the way so that the work area is free of interferences and the cables themselves are not damaged indirectly by the work in progress.
To conduct the test the cables must be unrolled, laid out and personnel locked out of the area for the duration of the test (16 hour1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br />s/week).
Upon test completion the cables are rolled back up and again tied out of the way.
The roll up and down requires 8 man hours/week and flexes the cables causing wear points and in turn breaks in the cable/connector protector tube.
In addition to this mode of damage they can be inadvertently damaged during control rod drive (CRD) maintenance.
During each outage approximately 20% of all CRDs are removed for maintenance and during removal, in the confined workspace, cables can be impacted by the removal tools.
The allowance to tie the cables up once each 92 day period would avoid the first method of damage.
Because the tie ups would not be repeated on a
weekly basis during the CRD repair effort the potential for an inadequate tie up and
4 t
Page Three
~
~
RE(UEST FOR AMENDMENT TO TS TABLE 4.3.6-1 SRM/IRM DETECTOR NOT-FULL-IN FUNCTIONAL TEST subsequent impact damage would be reduced.
Some amount of cable damage in this confined work space occurs each outage.
There are many cables routed through this area that can become damaged and the SRH/IRH cables are a
significant portion of this group.
Cable repair during the last outage required approximately 300 man hours and incurred approximately 3
man rem.
Working conditions in this area are extreme:
double anti-contamination clothing with either respirator or bubble hoods are required.
Health Physics supervision of this area and personnel is required but not included in the above figures.
As discussed in-the remainder of this request the proposed 'hange provides no significant hazards increase over the existing technical specification yet avoids manpower expenditure, radiation exposure, exposure of personnel to extreme work conditions, and challenges to SRH/IRH operability.
Approval of the requested amendment relieves the above hardships yet maintains the safety of the plant.
As described above the SRM/IRH Detector not-full-in Channel Functional Tests verify that plant circuits prohibit rod* movement in the REFUEL mode whenever an IRH/SRH detector is not in the full-in position.
This is to assure that the detectors are in an optimum position for monitoring the core in the event of rod movement and will be able to generate an upscale reading should equipment failures and/or inadvertent operator error occur.
Administrative controls on the SRH/IRH control system and daily verification of position full-in, as proposed, provide assurance that should the rod block instrumentation be inoperable and remain so the detectors will be positioned correctly.
It is the intent that the daily verification of position full-in will consist of viewing the detector mechanism in the under-vessel region to confirm correct positioning.
Failure to confirm correct positioning would imply failure of the channel functional test and the operability of the not-full-in instrumentation would have to be verified by performance of the functional test requiring movement of the detectors.
Hence, with administrative controls and the daily SRM/IRH position verification a
Rod Block function based on detectors not-full-in is not necessary.
Detector position will be assured.
The 92-day interval allowed for the channel functional test in the REFUEL mode is consistent with channel functional test extensions recently approved by the Staff in Reference 2.
In the Reference 2 Topical Report channel functional tests for Rod Block monitor,
- APRH, Scram Discharge Volume and Reactor Coolant System Recirculation Flow signals were extended from monthly to quarterly for the Control Rod Block Instrumentation Surveillance requirements.
The 92 day interval proposed herein is consistent with the extension approved in Reference 2 and allows similar conclusions to be drawn, i.e.,
the benefit of avoiding the above hardships offset any potential negative impact of extending the channel functional test.
The detector not-full-in rod block signal will remain in service and even should it fail the upscale SRH/IRH rod block signal will be operational. It should also be noted that the upscale Rod Block Instrumentation will continue to be surveyed weekly assuring the operability of that portion of the Rod Block function.
I
~ L
Page Four RE(VEST FOR AMENDMENT TO TS TABLE 4.3.6-1 SRH)IRH DETECTOR NOT-FULL-IN FUNCTIONAL TEST The requested revision will "add a
footnote to the required weekly (W) channel functional test for both the IRH and SRH function.
This footnote will state, "This CHANNEL FUNCTIONAL TEST may be satisfied while in MODE 5
provided the detector is administratively controlled in the full in position and is visually verified to be full in once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, unless the CHANNEL FUNCTIONAL TEST has not been performed within the past 92 days."
By verifying the detector is not retracted, the rod block provided by this function is not necessary, and the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> frequency with administrative controls will assure the detector remains full in.
Verifying within the past 92 days that the function performs as designed to produce a rod block if not full in, gives assurance that system reliability is adequate and any inadvertent withdrawal of a detector will still result in a rod block.
The Supply System has evaluated this amendment request per IOCFR 50.92 and determined that it does not represent a significant hazard because it does not:
I)
Involve a significant increase in the probability or consequences of an accident previously evaluated.
The subject rod block function does not significantly enhance protection against inadvertent criticality.
In MODE 5 the analyzed events of concern are discussed in the FSAR Section 15.4, Reactivity and Power Distribution Anomalies, specifically the Rod Withdrawal Error at Low Power.
The Neutron Monitoring System, including SRHs and IRHs does not function to preclude initiation of any aspect of this event.
The probability of this HODE 5
event is precluded by procedural controls and refueling equipment interlocks including the Reactor Hode Switch.
Since the probability of inadvertent criticality during refueling is precluded, without reliance on the SRHs or
- IRHs, and because no other credit is taken for the SRH/IRH feature in Mode 5
this change can not increase the probability or consequences of an accident previously evaluated.
In addition to the
- above, the compensatory actions described ensure that there is no significant change in the level of protection provided by this change.
Movement is precluded by the administrative controls and confirmation that no movement has occurred provides a defense-in-depth assurance that the level of protection is not compromised.
2)
Create the possibility of a new or different kind of accident from any accident previously evaluated.
The SRH and IRH systems provide for monitoring of neutron flux levels.
Maintaining the detectors in the required full in position is necessary for proper monitoring during operation with control rods withdrawn.
During MODE 5, refueling interlocks preclude the withdrawal of more than one rod and any one rod withdrawn will not result in criticality.
Should the.rod block for the IRH/SRH detectors not-full-in function fail, the other refueling interlocks would still preclude withdrawing more than one rod.
To assure
4 "I
t'
Page Five REQUEST FOR AHENDHENT TO TS TABLE 4.3.6-1 SRH/IRH DETECTOR'NOT-FULL-IN FUNCTIONAL TEST the detectors remain full in, administrative control s and a
daily surveillance is being added.
This will ensure proper neutron monitoring, and in conjunction with other unaffected refueling interlocks, will not allow this change to create the possibility of a new or different kind of accident from any previously evaluated.
3)
Involve a significant reduction in a margin of safety.
The Rod block for the IRH/SRH detectors not-full-in function remains unaffected by this change.
The surveillance performed to verify the function is operable will be performed at the beginning of a refueling outage.
During the outage the detectors will be required to be administratively controlled and visually verified to be full in at least once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
Haintaining the detectors in the full in position precludes the need for a detector not-full-in automatic rod block. If the detector is to be withdrawn, or this situation exists for more than 92 days, the original channel functional test would have to be performed or the channel declared inoperable.
The 92 day, allowance places a
reasonable restriction on this allowance and ensures a
high degree of reliability without imposing undue hardship, and is generally consistent with other functional test frequencies justified by the BWROG and approved by the Staff in Reference 2.
I I
Since the detectors will be maintained in their required position for monitoring, and the automatic rod block function is still verified to be operable in the event of an inadvertent detector withdrawal, there will not be a significant reduction in the margin of safety.
As discussed
- above, the Supply System considers that this change does not involve a significant hazards consideration, nor is there a potential for significant change in the types or significant incr ease in the amount of any effluents that may be released offsite, nor does it involve a significant increase in individual or cumulative occupational radiation exposure.
In fact, the change will result in a decrease in individual and cumulative occupational radiation exposure.
Accordingly, the proposed change meets the eligibility criteria for categorical exclusion set forth in 10CFR 51.22(c)(9) and therefore, per 10CFR 51.22(b),
an environmental assessment of the change is not required.
This Technical Specification change has been reviewed and approved by the WNP-2 Plant Operations Committee (POC) and the Supply System Corporate Nuclear Safety Review Board (CNSRB).
In accordance with 10CFR 50.91, the State of Washington has been provided a copy of this letter.
4~
1' s
1 I
N P
P 1,
V
'age Six REQUEST FOR AMENDMENT TO TS TABLE 4.3.6-1 SRM/IRM DETECTOR NOT-IN FUNCTIONAL TEST The next refueling outage for WNP-2 will be Spring 1990, tentatively scheduled to start on April 15, 1990.
Accordingly, to avoid the impact on plant safety, system reliability and manpower resources described above it would be beneficial if this proposal was approved at that time.
Very truly yours, G.
C. Sorensen, Manager Regulatory Programs PLP/bk Attachments cc:
JB Hartin -
NRC RV NS Reynolds BCP&R RB Samworth -
NRC DL Williams - BPA/399 NRC Site Inspector
- 901A C Eschels EFSEC
I tq
'f
STATE OF WASHINGTON)
)
COUNTY OF BENTON
)
Req. for Amend. to TS T 4.3.6-1
Subject:
SRM/IRM Detector not-full-in Func. Test I,
G.
C. Sorensen, being duly sworn, subscribe to and say that I am the Manager, Regulatory Progr ams, for the WASHINGTON PUBLIC POWER SUPPLY
- SYSTEM, the applicant herein; that I have full authority to execute this oath; that I have reviewed the foregoing; and that to the best of my knowledge, information, and belief the statements made in it are true.
DATE Z I9 dI 1989 G.
C.
S rensen, Manager Regulat ry Programs On this day personally appeared before me G.
C. Sorensen, to me known to be the individual who executed the foregoing instrument, and acknowledged that he signed the same as his free act and deed for the uses and purposes herein mentioned.
GIVEN under my hand and seal this~ day of 1989.
~i Notary Public in and or the STATE OF WASHINGTON Residing at My commission expires 7 14 91
I l
~
c V
1.
W, k
c, ~zjlti>4eSggg~
4 P
,/
z,"~l J>>"
>p~,
i I,